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The effect of eutrophication on aquatic plants (Elodea)
Transcript of The effect of eutrophication on aquatic plants (Elodea)
inorganic carbon activity
(Barko et al. 1986)
Fertilizer will affect the above factors by increasing the growth of algae. The pH will cause harm to animals and their habitat (Khan and Ansari 2005)
Light will not be able to reach the plants due to algal bloom, causing a decrease in temperature
Aquatic Plant Growth Limiting Factors
The Effect of Eutrophication on Aquatic Plants (Elodea)
Effects of Fertilizer Run-off
Results and Trends
Effect of Increased Biomass on Ecosystem
Eutrophication and Growth of Elodea
Increase of eutrophication results in
Since algae and surface plants are suspended at top, light is unable to penetrate deep into the water
is rooted at the bottom of the body of water
Light is unable to reach
, thus no photosynthesis
No photosynthesis = no plant growth (Morris et al. 2013)
Nutrient levels would increase
Increased nutrients would increase other aquatic plants as well as certain aquatic organisms that feed on these plants
Fish increase algal growth by increasing nutrient input, chlorophyll
concentrations were higher in areas of increased
biomass (Koenijów et. al 2005)
Increased biomass of
decreased amount of zooplankton (Koenijów et. al 2005)
Phytoplankton population was controlled by
because in areas of low
density, higher quantities of zooplankton were present, allowing zooplankton to feed on phytoplankton to control the population (Koenijów et. al 2005)
Figure 1: Mean change in biomass (g) of aquatic plant
after three weeks of eutrophication treatment with variable concentrations of fertilizer added. Each mean is the average of 43 replicates. Bars indicate ± SEM.
Hypoxia is the loss of oxygen content in water
Increased fertilizer causes algae blooms, consuming most of the dissolved oxygen in the water (Diaz and Rosenburg 2008).
This can cause aquatic organisms to die and therefore effect the whole ecosystem and cause a loss of habitat and food (Diaz and Rosenburg 2008).
Since fertilizers are being used on crops to increase nutrient levels, hypoxia is inevitable and makes it difficult for organisms and plants to thrive in their ecosystem (Diaz and Rosenburg 2008)
Non-linear decrease in mean biomass change after 0.156 g of fertilizer added (Figure 1)
The addition of 0.156 g of fertilizer caused an increase in biomass change rather than a decrease, contradicting the general trend (Figure 1)
Overlapping SEM bars for 0.312 g and 0.624 g of fertilizer indicate a similar biomass change for these treatments (Figure 1)
0.156 g of fertilizer had the greatest magnitude of biomass change at 1.95 ± 0.27 g (Figure 1)
Between 0 g (mean biomass change of 1.37 ± 0.18 g) and 2.808 g (mean biomass change of -1.07 ± 0.21 g) of fertilizer added, there was a biomass change decrease of 128% (Figure 1)
Increased eutrophication, resulting from fertilizer run-off, will decrease the biomass of the aquatic plants of the effected area.
Eutrophication leads to a decreasing biomass change in
Decreases in water oxygen levels damage all ecosystems because of the loss of habitat and food source from decreased plant life
Experiments and Questions
Reliability Of Data
Experiment adding other factors that change the environment (simulating boat pollution or climate change)
A study to manipulate the effects of individual nutrients on
Repeat this experiment with other species of aquatic plants to examine if they respond differently to eutrophication
The results support the hypothesis to an extent. The change in biomass of
decreases as eutrophication increases. However, after the addition of 0.156 g of fertilizer, the biomass change of
increased (Figure 1). This increase in biomass did not support the hypothesis.
Potential experiments to increase understanding
Questions from results
Does our experiment consider all of the variables of natural eutrophication? How effectively does a microcosm represent the eutrophication of an aquatic ecosystem?
What caused the increase in biomass change after the addition of 0.156 g of fertilizer?
Is there a specific nutrient in the fertilizer that is responsible for most of the biomass decrease?
Data is fairly reliable due to relatively small SEM's
Validity of data is reasonable because the literature supports the decrease in aquatic plants from over saturation of nutrients
The only discrepancy between the literature data and the experimental data was the increase in biomass change after the addition of 0.156 g of fertilizer.
Large increase in biomass change from 0 g to 0.156 g of fertilizer could be explained by initial increase in nutrients that favors plant growth without reducing water quality. Nutrient toxicity may not have affected growth until higher levels of fertilizer were added.
Over saturation of nutrients has lead to a decrease in aquatic plants (Anderson et al. 2002)
Another study by Carpenter et al. (1998) also found that increase of nutrients causes a decrease in the amount of aquatic plants
Consequences of degradation in water quality due to eutrophication outweigh the advantages of the increased nutrient content because of elevated water pH and depletion of dissolved oxygen (Smith et al. 1999)
Anderson DM, Gilbert PM, Burkholder JM. 2002. Harmful algal blooms and eutrophication: nutrient sources, composition, and consequences. Estuaries. 25(4b): 704-726.
Barko JW, Adams MS, Clesceri NL. 1986. Environmental factors and their consideration in the management of submersed aquatic vegetation: a review. Journal of Aquatic Plant Management. 24(1): 1-10.
Carpenter SR, Caraco NF, Correll DL, Howarth RW, Sharpley AN, Smith VH. 1998. Nonpoint pollution of surface waters with phosphorus and nitrogen. Ecological Applications. 8(3): 559-568.
Khan FA, Anasari AA. 2005. Eutrophication: an ecological vision. The Botanical Review. 71(4): 449-482.
Kornijów R, Vakkilainen K, Horppila J, Luokkannen E, Kairesalo T. 2005. Impacts of a submerged plant (
) on interactions between roach (
) and its invertebrate prey communities in a lake littoral zone. Freshwater Biology. 50(2): 262-276.
Morris J, Hartl DL, Knoll AH, Lue RA. 2013. Biology: How Life Works. New York City: W. H. Freeman and Company.
Rosenburg R, Diaz RJ. 2008. Spreading dead zones and consequences for marine ecosystems. Science. 321(5891): 926-929.
Smith VH, Tilman GD, Nekola JC. 1999. Eutrophication: impacts of excess nutrient inputs on freshwater, marine, and terrestrial ecosystems. Environmental Pollution. (1-3): 179-196.
Spicer KW, Catling PM. 1988. The biology of Canadian weeds. Canadian Journal of Plant Science. 68(4): 1035-1051.
is a native North American aquatic plant that obtains its elemental composition from sediments. It is found in submerged aquatic plant communities and is tolerant of eutrophication changes. The phosphorous levels within the plant indicate water nutrient levels and is often used as an indicator of water quality (Spicer and Catling 1988)
Biotic factor: growth of algae
Abiotic factor: amount of light
Eutrophication causes increased algae growth, decreasing the light available to aquatic plants
Eutrophication Effect on Abiotic and Biotic Factor